1. Field of the Invention
The present invention is broadly concerned with improved wheat flour-based leavened foods (e.g., breads of various types) which exhibit reduced toughness when subjected to microwave heating. More particularly, the invention is concerned with such products, as well as their precursor doughs, wherein the gliadin:glutenin ratios of the doughs are adjusted to a level of from about 1.1-2.3. Preferably, such ratio adjustment is accomplished by the addition of minor amounts of a gliadin-rich preparation into the doughs.
2. Description of the Prior Art
Wheat flour contains variable amounts of protein with 10% being normal for bakery flour. Of this 10% protein, about 85% is gluten protein with the remainder being water and salt soluble proteins. Thus, in 100 g of bakery flour there are about 8.5 g of gluten protein, which contains about 48% gliadin and 52% glutenin, or 4.08 g gliadin and 4.42 g glutenin. Hence, the gliadin:glutenin ratio for such flour is about 0.92.
It is well known that stale bread products can be refreshed by heating. However, bread reheated in a microwave oven often becomes tougher (i.e., rubbery and difficult to masticate). Although the mechanism of bread toughening is not clearly understood, formula modifications have been shown to reduce microwave-induced toughness of reheated bread. These include the addition of certain emulsifiers, a combination of emulsifiers and pregelatinized starch, and a combination of high levels of shortening and added fiber.
Notwithstanding these prior efforts, the problem of microwave-induced toughening of breads and similar products remains largely unresolved. As can be appreciated, this problem is particularly acute with many convenience foods such as sandwiches or bread-based pizza products. In such cases, consumers often prefer to microwave heat the products to save time and eliminate the need of conventional oven heating. However, bread products in the prior art often become unacceptably chewy and tough as a result of microwave heating. As a consequence, the desirability and hence saleability of these snack food items is reduced.
There is accordingly a real and unresolved need in the art for improved bread and similar products having reduced microwave heating-induced toughness. At the same, any method to accomplish these ends must be relatively simple and inexpensive.
The present invention overcomes the problems outlined above, and provides an easy method for reducing microwave heating-induced toughness of wheat flour-based leavened foods made from starting ingredients containing wheat flour. Such doughs inherently have respective amounts of gliadin and glutenin therein, as a portion of the gluten fraction of the wheat flour. In the invention, the gliadin:glutenin ratio of the starting dough is adjusted to a level of from about 1.1-1.3, and more preferably from about 1.3-1.6.
In preferred forms, the ratio adjusting step involves the addition of a minor amount of a gliadin-rich preparation to the starting dough. As used herein xe2x80x9cgliadin-rich preparationxe2x80x9d refers to a fraction or preparation containing an amount of gliadin substantially above that of normal wheat flour. Usually, such a gliadin-rich preparation would contain at least about 50% by weight gliadin, and more preferably at least about 65% by weight. It will be understood in this respect that commercially available gliadin-rich preparations contain additional proteins such as glutenin as well as other ingredients, but these preparations do contain a substantial gliadin fraction. When such a commercial gliadin-rich preparation is added to a starting dough, it should be present in an amount of from about 1-6% (fwb), and more preferably from about 2-3% (fwb).
It will be understood that the principles of the invention have relatively broad applicability in terms of products. For example, conventional breads of various sizes and shapes can be improved in accordance with the invention, but also items such as sweet rolls and biscuits are also suitable. Normally, the products of the invention are yeast-leavened; however, the invention is not so limited, and improvement can be made with chemically leavened products as well. Generally, the products of the invention are baked, but fried, steamed or otherwise cooked products can also be improved via the invention.